Final answer:
The correct answer is option B) -4.5, which is a negative rational number that is not an integer.
Step-by-step explanation:
A negative rational number that is not an integer is an option B) -4.5. Rational numbers include all fractions, mixed numbers, and decimals that can be expressed as a fraction, and option B fits this definition while also being negative and not an integer. Option A) -π is an irrational number, option C) -0.83 is a negative rational number but an integer and option D) 15 is a positive integer.